Mechanical joint pipe connections are a common method for attaching a pipe length to a piping element such as a valve, a coupling, or a fitting, such as a tee or elbow, or another pipe. The mechanical joint pipe connection can comprise a female socket, a gland, a gasket, and a pipe length. The piping element commonly defines a female socket configured to receive a plain end of the pipe length and a gasket. A gland is commonly provided which slips over the plain end of the pipe length, and the gland is tightened by a series of bolts which draw the gland towards the female socket, thereby compressing the gasket. Compression of the gasket causes the gasket to engage an outer surface of the plain end of the pipe length, thereby forming a seal between the pipe length and the element.
Mechanical joint pipe connections are popular because mechanical joint pipe connections function with the plain end of the pipe length, unlike groove connections or flanged connections that require preparation of the plain end of the pipe length. The ability to function with the plain end allows for the pipe length to be cut to size in a field installation without requiring the time and field equipment necessary to weld a flange to the plain end or to cut a new groove in the plain end. Mechanical joint pipe connections can be assembled quickly with common hand tools such as a wrench or ratchet.
However, typical mechanical joint pipe connections do not provide for a positive retention mechanism other than friction of the gasket acting on the plain end of the length. The lack of a positive retention mechanism can compromise the seal or lead to the plain end pulling out of the female socket when the connection is subjected to high tension force or effects such as water hammer. Some mechanical joint pipe connections can incorporate a joint restraint mechanism configured to mechanically engage the plain end of the pipe; however, existing joint restraint mechanisms can exert high stresses upon the plain end of the pipe length which can lead to deformation, creep, and cracking of the plain end of the pipe length during installation or operation. Deformation, creep, and cracking can lead to failure of the seal or failure of the pipe length itself which can result in leaks or environmental contamination.